Hey guys.
I own a 02 1.8T A4 Avant. I work in a shop with my pop who has been running it for 30 years. So heres my problem.

A while ago my car needed a valve job, no problem. Finished, was running right. Then later, it was experiencing a loss of power. the symptoms (at least what we think) is that the wastegate for the turbo would a ton of times between the car being in 1 up to 3 (automatic). You can watch the tachometer literally start at 900, rise up, and when the wastegate would open, the tachometer stops at the current RPM, and then continues after the gate closes.

We found that we had swapped two coils on incident, and swapped them again, which relieved the problem.

Now, nearly a year later, I'm experiencing the same symptoms again. The car is not throwing any codes besides bs O2 codes.

We are frikkin stumped. We have no idea what's going on with the car.